From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932623AbcFOKUf (ORCPT ); Wed, 15 Jun 2016 06:20:35 -0400 Received: from foss.arm.com ([217.140.101.70]:36044 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753287AbcFOKSf (ORCPT ); Wed, 15 Jun 2016 06:18:35 -0400 From: Juri Lelli To: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, peterz@infradead.org, vincent.guittot@linaro.org, robh+dt@kernel.org, mark.rutland@arm.com, linux@arm.linux.org.uk, sudeep.holla@arm.com, lorenzo.pieralisi@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, juri.lelli@arm.com, broonie@kernel.org, sgurrappadi@nvidia.com Subject: [PATCH v5 2/8] arm: parse cpu capacity-dmips-mhz from DT Date: Wed, 15 Jun 2016 11:17:51 +0100 Message-Id: <1465985877-18271-3-git-send-email-juri.lelli@arm.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1465985877-18271-1-git-send-email-juri.lelli@arm.com> References: <1465985877-18271-1-git-send-email-juri.lelli@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With the introduction of cpu capacity-dmips-mhz bindings, CPU capacities can now be calculated from values extracted from DT and information coming from cpufreq. Add parsing of DT information at boot time, and complement it with cpufreq information. We keep code that can produce same information, based on different DT properties and hard-coded values, as fall-back for backward compatibility. Caveat: the information provided by this patch will start to be used in the future. We need to #define arch_scale_cpu_capacity to something provided in arch, so that scheduler's default implementation (which gets used if arch_scale_cpu_capacity is not defined) is overwritten. Cc: Russell King Signed-off-by: Juri Lelli --- Changes from v1: - normalize w.r.t. highest capacity found in DT - bailout conditions (all-or-nothing) Changes from v4: - parsing modified to reflect change in binding (capacity-dmips-mhz) --- arch/arm/kernel/topology.c | 145 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 144 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index ec279d1..2bab290 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -78,6 +78,134 @@ static unsigned long *__cpu_capacity; #define cpu_capacity(cpu) __cpu_capacity[cpu] static unsigned long middle_capacity = 1; +static bool cap_from_dt = true; +static u32 *raw_capacity; +static bool cap_parsing_failed; +static u32 capacity_scale; + +static int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) +{ + int ret = 1; + u32 cpu_capacity; + + if (cap_parsing_failed) + return !ret; + + ret = of_property_read_u32(cpu_node, + "capacity-dmips-mhz", + &cpu_capacity); + if (!ret) { + if (!raw_capacity) { + raw_capacity = kzalloc(sizeof(*raw_capacity) * + num_possible_cpus(), GFP_KERNEL); + if (!raw_capacity) { + pr_err("cpu_capacity: failed to allocate memory" + " for raw capacities\n"); + cap_parsing_failed = true; + return !ret; + } + } + capacity_scale = max(cpu_capacity, capacity_scale); + raw_capacity[cpu] = cpu_capacity; + pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n", + cpu_node->full_name, raw_capacity[cpu]); + } else { + pr_err("cpu_capacity: missing %s raw capacity " + "(fallback to 1024 for all CPUs)\n", + cpu_node->full_name); + cap_parsing_failed = true; + kfree(raw_capacity); + } + + return !ret; +} + +static void normalize_cpu_capacity(void) +{ + u64 capacity; + int cpu; + + if (WARN_ON(!raw_capacity) || cap_parsing_failed) + return; + + pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); + for_each_possible_cpu(cpu) { + capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) + / capacity_scale; + set_capacity_scale(cpu, capacity); + pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", + cpu, arch_scale_cpu_capacity(NULL, cpu)); + } +} + +#ifdef CONFIG_CPU_FREQ +static cpumask_var_t cpus_to_visit; +static bool cap_parsing_done; + +static int +init_cpu_capacity_callback(struct notifier_block *nb, + unsigned long val, + void *data) +{ + struct cpufreq_policy *policy = data; + int cpu; + + if (cap_parsing_failed || cap_parsing_done) + return 0; + + switch (val) { + case CPUFREQ_NOTIFY: + pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] " + "(to_visit=%*pbl)\n", + cpumask_pr_args(policy->related_cpus), + cpumask_pr_args(cpus_to_visit)); + cpumask_andnot(cpus_to_visit, + cpus_to_visit, + policy->related_cpus); + for_each_cpu(cpu, policy->related_cpus) { + raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) * + policy->max / 1000UL; + capacity_scale = max(raw_capacity[cpu], capacity_scale); + } + if (cpumask_empty(cpus_to_visit)) { + normalize_cpu_capacity(); + kfree(raw_capacity); + pr_debug("cpu_capacity: parsing done\n"); + cap_parsing_done = true; + } + } + return 0; +} + +static struct notifier_block init_cpu_capacity_notifier = { + .notifier_call = init_cpu_capacity_callback, +}; + +static int __init register_cpufreq_notifier(void) +{ + if (cap_parsing_failed) + return -EINVAL; + + if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) { + pr_err("cpu_capacity: failed to allocate memory for " + "cpus_to_visit\n"); + return -ENOMEM; + } + cpumask_copy(cpus_to_visit, cpu_possible_mask); + + return cpufreq_register_notifier(&init_cpu_capacity_notifier, + CPUFREQ_POLICY_NOTIFIER); +} +core_initcall(register_cpufreq_notifier); +#else +static int __init free_raw_capacity(void) +{ + kfree(raw_capacity); + + return 0; +} +core_initcall(free_raw_capacity); +#endif /* * Iterate all CPUs' descriptor in DT and compute the efficiency @@ -99,6 +227,12 @@ static void __init parse_dt_topology(void) __cpu_capacity = kcalloc(nr_cpu_ids, sizeof(*__cpu_capacity), GFP_NOWAIT); + cn = of_find_node_by_path("/cpus"); + if (!cn) { + pr_err("No CPU information found in DT\n"); + return; + } + for_each_possible_cpu(cpu) { const u32 *rate; int len; @@ -110,6 +244,13 @@ static void __init parse_dt_topology(void) continue; } + if (parse_cpu_capacity(cn, cpu)) { + of_node_put(cn); + continue; + } + + cap_from_dt = false; + for (cpu_eff = table_efficiency; cpu_eff->compatible; cpu_eff++) if (of_device_is_compatible(cn, cpu_eff->compatible)) break; @@ -151,6 +292,8 @@ static void __init parse_dt_topology(void) middle_capacity = ((max_capacity / 3) >> (SCHED_CAPACITY_SHIFT-1)) + 1; + if (cap_from_dt && !cap_parsing_failed) + normalize_cpu_capacity(); } /* @@ -160,7 +303,7 @@ static void __init parse_dt_topology(void) */ static void update_cpu_capacity(unsigned int cpu) { - if (!cpu_capacity(cpu)) + if (!cpu_capacity(cpu) || cap_from_dt) return; set_capacity_scale(cpu, cpu_capacity(cpu) / middle_capacity); -- 2.7.0